KR20200037099A - Bacteria removal laser - Google Patents

Abstract

Provided is a bacteria removal laser for removing caries bacteria particularly from natural or prosthetic tooth, wherein the caries bacteria from the latter can be removed from the outside of the mouth. The bacteria removal laser comprises a gripping handle, a laser radiation source, a preset radiation exit surface, a working optic having a radiant ray guide rod which is specifically passed by laser radiation, and an energy source such as a power connection part or a storage battery. Laser is emitted in a wavelength range from 2,200 to 4,000 nm, and is specifically designed as Er:YAG laser. The average energy outputted over time is less than 1 mJ/mm^2 at the radiation exit surface.

Description

Bacteria removal laser {BACTERIA REMOVAL LASER}

The present invention relates to a bacteria removal laser according to the premise of claim 1 and a system according to claim 13.

For the removal of bacteria that have attacked the hard and / or soft tissues of humans or animals, it has long been known to use sterile substances.

This includes antibiotics in particular. In addition to the resistance developed by antibiotic administration, antibiotics are inappropriate or ineffective when affecting deep tissue layers. This is especially true for hard tissue.

Hard tissue includes, among other things, human and animal teeth. They are often infected with caries with caries bacteria, including Streptococcus mutans.

In general, tooth decay is treated to remove the tooth decay material using a standard dental drill.

The tooth is damaged by removing hard tooth tissue. Nevertheless, in order to ensure that the dental caries bacteria do not remain under the dental restoration that the dentist subsequently manufactures, it is required to remove slightly more than the dental caries material affected as a precautionary measure.

Other measures are also known to avoid tooth decay. This includes, for example, fluorination and tooth decay infiltration with special fluoride formulations. In this case, the low-viscosity plastic must be introduced into the dental caries tissue, forming a diffusion barrier.

In addition, a cover with calcium hydroxide or free ionomer cement is known.

In addition, the use of laser light for the treatment of cavities has been known for over 20 years. According to EP 1 052 947 A1, tooth decay bacteria must be vaporized with an Nd: YAG laser. In order to achieve the desired effect, since 1 to 10 watts of laser power is used, intensive irradiation of the treatment surface by laser radiation can occur. There is no depth effect.

However, testing this technique for the past 20 years has shown no long-term success. Although the expansion of the cavities may appear to be stationary on the surface, the cavities expand in the long term when using this technique, such as short or short dental implants, such as replacement of hard teeth material affected by onlay or crown or root canal treatment. Longer radical measures are needed.

If these measures are not taken, there is a risk that the adjacent teeth and, if necessary, antagonists are also decayed.

On the other hand, it is also an object of the present invention to provide a system consisting of a bacteria removal laser according to the preamble of claim 1 and a bacteria removal laser according to the preamble of claim 13 and a treatment surface, which act in the long term.

This object is achieved according to the invention according to claim 1 or 13. An advantageous development example comes from the dependent claims.

According to the invention, the bacteria removal laser is designed as a handheld device. Thus, it includes a handle that allows the direction and spatial position of the laser radiation emission of the laser radiation source to be controlled.

The laser radiation source can also be in the hand piece or, if necessary, in a fixed base station connected to the grip handle by a flexible radiation guide rod. The grip handle also has a radiation exit surface, at which point the radiation emitted by the laser radiation source leaves the laser.

A working optic is connected upstream or downstream of the radiation guide rod or is provided on both sides. It can be used, for example, for homogenizing radiation, or, if necessary, for bundling emitted radiation.

The laser is emitted in the wavelength range of 2200 nm to 4000 nm. In this regard, Er: YAG lasers with emission of up to about 2940 nm are suitable.

Alternatively, GaInAsSb lasers, GaInSn lasers or GaInSb / GaSb lasers emitted between 2100 nm and 4000 nm are also possible.

The laser also operates by, for example, microwave emitters, for example in the frequency range of 2 to 3 GHz, forming a major.

Lasers with long wavelengths are not recommended for use in the human body, ie in the long infrared region, for example because the skin tends to burn with strong laser light action at this wavelength.

In addition, it is pointed out in the standard literature that laser radiation with a larger wavelength has a lower passing depth due to the maximum absorption of water present therein.

However, according to the present invention, the present bacteria removal laser has this wavelength and an average energy output over a time of less than 1 mJ / mm ² .

Surprisingly, this laser action results in the sustainable removal of bacteria. The action time is at least several minutes, preferably 10 to 15 minutes, for the corresponding high pass depth.

A high absorption capacity of water at about 3000 nm is used. When the laser is applied, water evaporates on and below the treated surface at a temperature well below 100 degrees Celsius.

Bacteria located there appear to be co-evaporated or at least damaged.

For example, when the water of the first layer having a layer thickness of 1 mm evaporates, the laser radiation that is no longer absorbed by water passes deeper, acting on the next millimeter.

In this way, the action by the laser radiation according to the invention for the removal of bacteria occurs until the caries bacteria present in the deeper layers below the treatment surface are damaged.

According to the present invention, it is advantageous to select the energy density and power of the bacteria removal laser so that only a few degrees of temperature increase, eg, up to 8 degrees or up to 15 degrees, in the teeth. As a result of the investigation, it was found that it is important for the temperature to rise slowly to eliminate the risk of stress cracking on the tooth surface. Preferably, the temperature increase is less than 20 degrees / minute, more preferably less than 15 degrees / minute.

The preferred maximum temperature of the treated surface is 45 degrees Celsius. Here, the selection of an appropriate pulse / stop ratio has an advantageous effect. For example, the pulse / stop ratio can be 1 to 20 or 1 to 30. This represents an advantageous compromise.

According to the present invention, it is sufficient if the bacteria are damaged to such an extent that the bacteria can no longer reproduce and no longer produce "acid / metabolites".

It is not necessary to destroy the cell wall by vapor pressure, ie to place it by evaporation at 100 ° C., it is sufficient to heat it to a substantially lower temperature, similar to pasteurization.

The use of a bacteria removal laser according to the invention also avoids the need to use a separate coolant. This eliminates the risk of thermal stresses and microcracks on the tooth surface. When water cooling is removed, a high possibility of laser movement is possible.

Although the dental prosthesis is of course not caries, the bacterial removal laser according to the invention can be used to "sterilize" it, because bacteria present therein, for example Streptococcus mutans, can also be damaged according to the invention. Because there is.

Since oral hygiene is particularly important, it is especially recommended for partial dentures.

A special advantage of using a laser radiation of about 3000 nanometers is that both dentin and enamel are substantially transmissive to this wavelength. Of course, this does not apply to wet dental hard tissue. Water and thus bacteria are also particularly well absorbed at the wavelengths mentioned.

The combination of these features can be exploited by the fact that by prolonging the action time of the laser, even deeply present bacteria are easily accessible according to the invention.

When water and bacteria are present in the affected area, the introduced laser radiation weakens as the depth of passage increases. Absorption consists, for example, of 15% to 25% per mm, or for example of 20% to 35% per mm penetration depth.

However, as the depth of passage increases as the removal and drying of bacteria in the hard tooth tissue increases, the area where the laser radiation is weakened is displaced to the inside of the tooth, ie dentin.

Through this desirable effect, it is possible to ensure the removal of deeply located bacteria.

Surprisingly, these deeply located bacteria can also be made harmless.

It is advantageous for the bacteria removal laser to have a sensor intended to detect radiation reflected by the treatment surface or radiation transmitted through the treatment surface and the lower region.

You can also combine the two types of detection.

In particular, the transmissive sensor can detect which radiation passes through the treatment surface and the lower region, that is, the treatment surface.

For example, it can be deduced from the increase in the output signal of the sensor that sufficient moisture and bacteria can be removed to complete the treatment.

It is also possible to measure at the radiation stop of the pulsed laser radiation. In this case, the sensor detects the emission of the treatment surface at an appropriate wavelength range, for example from 1000 to 14000 nm, for example at 3000 nm up to the temperature of the teeth.

The temperature is preferably measured during irradiation, advantageously in the wavelength range of 1-2.8 micrometers or 3.5-14 micrometers, ie outside the maximum emission range of the Er: YAG laser.

The bacteria removal laser preferably has a control device. This serves to turn the laser on and to pre-determined but preferably to copy for a selectable amount of time or to turn off the laser once removal of the caries bacteria is complete.

For example, radiation relative to the sensor may reduce radiation if the treatment surface becomes too warm. In this case, treatment is preferably extended automatically.

Preferably, the radiation exit surface is smaller than the teeth. The diameter can be 1 to 7 mm, preferably circular and preferably has a diameter of 4 mm.

The laser according to the invention is preferably coupled to a source of sterile water. Thereby, the treated surface after treatment is rinsed and wetted simultaneously, so that accidental overdrying of the treated surface can be avoided. The sterile water source can also be used connected downstream, in which case it is functionally assigned to the laser in any case, even if the laser is not installed.

The invention is also presented in a system consisting of a bacteria removal laser and a treatment surface. According to the present invention, it is provided that the laser emits radiation in a wavelength range of 1500 to 4500 nm, in particular over 2200 nm, and supplies it to the treatment surface.

During the onset of radiation transfer, laser radiation is absorbed at 20-35% per mm pass depth. Therefore, it damages or destroys bacteria.

In one embodiment, the radiation reaches the treatment surface with an average energy density over time of 0.01 mJ / mm ² to 10 mJ / mm ² .

The present invention enables the use of bacterial removal lasers for the removal of caries bacteria for the removal of caries bacteria, in particular their metabolism, their genetic makeup and / or fatal removal.

Other advantages, details and features will become apparent from the following description of embodiments of the invention with reference to the drawings.

1 is a schematic perspective view showing a bacteria removal laser according to the present invention as an action for removing tooth decay bacteria in the first embodiment.
2 shows another embodiment of a bacteria removal laser with a sensor according to the invention.
3 shows a third embodiment of a bacteria removal laser according to the invention.
4 shows a schematic of hard tissue with the bacteria shown.
5 shows an increase in the depth of penetration of the laser radiation into the hard tissue.
6 is a graph of measured temperature increase in wet compared to dry teeth.
7 shows the temperatures measured by temperature sensors in dry and wet teeth.

From Fig. 1, the bacterial removal laser of the first embodiment can be seen. The bacteria removal laser 10 has a radiation source 12, which is accommodated in a base station and in particular connected to a handheld device via a heat-transmissive light guide. If necessary, everything can be realized even in the head area of the handheld device. The handheld device has a gripping handle 14 through which the operator can bring it to a desired position.

In the head area of the handheld device, a working optic 16 through which the laser beam generated by the radiation source 12 passes is arranged.

Radiation guide rods 18 ending at the radiation exit surface 20 are arranged.

The handheld device has a power connection 19 and a control device 21 that form a power source.

The radiation source is designed with an Er: YAG laser and emits laser radiation with emission of up to 2940 nanometers.

The laser radiation 22 strikes the treatment surface 24. It is formed in the molar 25 in this embodiment, and the occlusal surface is infected with the cavities 26.

In this example the treated surface is a circular area with a diameter of 1 mm. The size of this area can be tailored to your needs in many areas. For example, the diameter can be 5 mm.

The size of the treated surface is also adjustable. To this end, the acting optics 16 have corresponding adjustment possibilities.

Preferably, the size of the treated surface is typically as large as the area infected by the cavities, ie 3 mm in diameter. If the diameter is smaller than the area infected with the cavities, the operator must move the treatment surface through the entire area infected with the cavities to extend treatment.

According to the invention, the operator of the laser according to the invention first checks which area of the tooth 25 is infected by tooth decay. He directs the laser radiation to this area in a known manner, as is common in light curing equipment, and turns on the handheld device.

The laser radiation is pulsed at a pulse stop ratio of 1:30 and output.

Laser radiation with an energy density of less than 1 mJ / mm ² is averaged over time and output. This hits the treatment surface 24.

The operator holds this position for a few minutes.

Pulsed laser radiation damages caries bacteria in the area of the treatment surface 24. First, the surface area of the treated surface, ie directly below the surface, is mainly affected. The liquid present there, essentially saliva evaporates, allowing the laser radiation to pass deeper. Depending on the desired depth of passage, the radiation application may be maintained for 15 or 20 minutes.

Just below the treatment surface 24, the tooth 25 has a tooth enamel. The cavities bacteria typically pass through 1 to 3 mm here, where cavities can be induced without the bacteria removal laser 10 according to the invention.

In an advantageous embodiment of the present invention, it is provided to support the bacteria removal laser using a support device on the patient's lower jaw or jaw.

The support device, not shown, is adjustable and allows the laser beam 22 to specify where it strikes the desired treatment surface 24.

By means of the support device, the distance between the radiation exit surface 20 and the treatment surface 24 can also be adjusted. It is preferably 1 mm to 2 cm.

After the laser treatment is completed, the area originally infected by the caries bacteria is preferably rinsed with sterile water by a sterile water source 27. This compensates for saliva loss during treatment on the one hand and washes out dead bacteria on the other hand.

2 shows another embodiment of a bacteria removal laser according to the present invention. Here, the sensor 30 is attached to the side opposite the laser 10 in the tooth 25. The sensor detects laser radiation passing through the teeth 25. In particular, changes in laser radiation are detected.

After the laser radiation is absorbed in the area of the treatment surface 24, the absorption is lower due to the evaporation of the water therein or the liquid therein in the process, and the output signal of the sensor increases.

에 따라 증가하여, 통과 깊이는 이제 그에 상응하게 증가한다.It can be inferred that treatment has progressed from an increase in the output signal. For example, an increase of 3% could mean that there is now no life bacteria at a pass depth of 1 millimeter, so Lambert-Beer's law

With increasing, the passing depth is now correspondingly increased.

According to FIG. 2, the sensor 30 is disposed outside the optical axis of the laser 10. Consequently, scattering of the laser radiation at the teeth 25 is considered.

According to FIG. 3, the laser is placed on the optical axis such that after proper absorption, the laser radiation strikes the sensor 30 directly.

The sensor 30 according to FIGS. 2 to 3 is designed as a transmission sensor. It is also possible to realize a reflection sensor.

This reflective sensor is directed directly to the treatment surface 24. Since the wet treated surface 24 reflects more strongly than it is dried, the reflective sensor detects drying of the treated surface by laser radiation.

In FIG. 4, storage of caries bacteria 40 in hard tissue 42 can be seen as an example. In this example, the hard tissue is tooth enamel, where both liquid and bacteria can pass through. The crystal structure of the tooth enamel allows tooth decay bacteria to be distributed in three dimensions, where it generally begins to pass through the tooth surface.

Typically, the bacterial density is thus higher on the tooth surface, but for successful caries removal, it is necessary to damage the bacteria, even at least in less depth, to such an extent that they can no longer reproduce. This can be realized with the bacteria removal laser according to the invention.

The sensors 30 shown in FIGS. 2 to 3 can be measured at the wavelength of the laser 10. Alternatively and preferably, these are temperature sensors 30 located at any suitable location to measure at pulse spacing and / or wavelengths above or below the laser wavelength. The temperature sensor can be located at any suitable location.

Suitable inexpensive temperature sensors detect wavelengths from 1200 to 2500 nm.

In Figure 5 it can be seen how the action proceeds by the bacterial damage wavelength. First, the first layer 44 immediately adjacent to the treatment surface 24 is hit by the laser beam 22. The bacteria present here are damaged.

The cell wall can be damaged to destroy it, but any other removal is possible, for example, it is also possible to completely remove the liquid present in the cell by laser radiation.

As soon as the degree of moisture in the first layer 44 is significantly reduced, most of the laser radiation 22 reaches the region of the second layer 46. This is repeated for the third, fourth and fifth layers 48, 50 and 52, until the bacteria in the entire area of the caries 26 are destroyed or damaged.

The control device 21 controls the radiation source 12 so that the caries bacteria are first damaged in the upper layer of the teeth 25. Since it is heated and dried, the temperature increase is greater with the same laser power.

Preferably, the radiation source 12 is pulsed. It also turns on and off periodically, for example every 3 seconds.

After a period of time, all cavities in layer 44 are destroyed. From that point on, there will be a focus on removing the second layer 46 and the like.

The temperature of the teeth 25, especially the treatment surface 24, is permanently measured by the sensor 30 or other sensor.

If the temperature increase exceeds the threshold, this means that the caries bacteria are removed there. This can be inferred from the temperature gradient, which is monitored by the temperature control device 21.

Below are exemplary operating data of the bacteria removal laser 10 according to the present invention:

In another embodiment of the invention, the following operational data were used:

Laser parameters

wavelength 2.94 μm

I 300 A

frequency 150 Hz

tp 150 μs

Diameter focus 4 mm

Area 12.6 mm ²

Laser energy 0.72 W

Energy density

term 6.67 ms

Duty cycle 2.25%

Peak power 0.0048 W * s

Maximum power per area 0.000382 J / mm ²

0.3820 mJ / mm ²

Energy density

Energy density 0,00038197 J / mm ²

0.382 mJ / mm ²

Peak power

Max power 32 W * s

Energy per peak

Energy per peak 0.0048 J

Power density

Power density 0.0573 W / mm ²

Average power

Paverag (full time) 0.72 W

In addition, the theoretical removal or killing rate of caries bacteria was calculated:

Its diameter is about 0.1 to 700 μm, and in the most known type it is about 0.6 to 1.0 μm. Their length is in a wider range: in single cells between about 0.6 μm (cocci) and 700 μm, the mycelium can be longer, and most bacteria are 1 to 5 μm long. The volume of most bacteria is about 1 μm³.

Bacterial home

volume 1 μm3

Radius 0.620 μm

diameter 1.24 μm

Density of water 1 g / cm3

mass 1E-12 g

Mass bacteria 1.0E-06 μg

Temperature 298K

Hv 44.0 kJ / mol

10-6 μg of 100% water 2.45E-09 J

By 1 W 408'869'870 Bacteria / sec

This means that about 2.5E-09 W * s = 2.5E-09 Joules are needed to evaporate the bacteria. Assumptions: 100% water and 100% energy are converted to enthalpy of evaporation. Thus, about 400 million bacteria per second can be evaporated at 1 watt.

In FIG. 6, the temperature increase measured in operation of the bacteria removal laser 10 is shown as a comparison of “wet” and “dry”.

Dry teeth were taken and acted as general laser parameters (see above). At the same time, the temperature was measured. The heating rate (slope) in degrees per minute for the first minute after switching on was determined from the linear fit and is shown in FIG. 6. Dry teeth show faster heating because they do not require energy to evaporate water. This effect can be used for intelligent and individual determination of the end of processing as claimed in claim 8.

7 shows the heating curve of the teeth. It shows the increase in the temperature of wet and dry teeth.

It can be seen that the temporal temperature gradient of the dry teeth is quite high, where energization was stopped after about 1 minute and after evaluation, it was found that all moisture, including bacteria, disappeared.

In another preferred embodiment, a target beam with visible light is provided parallel to the laser beam. This allows him to be seen by the dentist being treated.

Claims (15)

Particularly natural or prosthetic teeth, in the latter case also as a bacteria removal laser for removing cavities from the maxilla, a gripping handle, a laser radiation source and a radiation guide rod passed by a preset radiation exit surface, in particular a laser radiation In the bacterial removal laser comprising a working optic having a power source and an energy source such as a storage battery,
The laser is emitted in the wavelength range of 2200 nm to 4000 nm, and is specifically designed as an Er: YAG laser having an average energy output of less than 1 mJ / mm ² at the radiation exit surface. According to claim 1,
A bacteria removal laser comprising a sensor that responds to radiation in the wavelength range from 1000 nm to 15000 nm and has a maximum sensitivity above or below the maximum emission value of the laser. The method of claim 1 or 2,
The sensor is designed as a reflection detection sensor, detects radiation reflected by the treated surface, and the reflected radiation passes through a working optic, in particular, a bacteria removal laser. The method according to any one of claims 1 to 3,
The sensor is designed as a transmission detection sensor, characterized in that it detects the radiation passing through the treatment surface-after refraction if necessary-characterized in that the bacteria removal laser. The method according to any one of claims 1 to 4,
The sensor of the laser detects the temperature at the original position of the treatment surface, and in particular at temperatures above 55 ° C, especially above 45 ° C, the control device for the laser reduces its energy output or reduces it to zero. Bacteria removal laser. The method according to any one of claims 1 to 5,
The laser radiation source emits pulsed laser radiation at a pulse / stop ratio of 1: 1 to 1: 1000, particularly 1: 5 to 1: 200, preferably about 1:25, and the power average over time is less than 2 W , More preferably about 0.8 watts. The method according to any one of claims 1 to 6,
The laser radiation source emits pulsed laser radiation at a period of 0.02 seconds to 0.002 seconds, for switching on and off the laser radiation source at a frequency of less than 2 W, with an average power of less than 1 Hz, preferably about 0.3 Hz. A switching device and / or a treatment surface protection device that can move in front of the radiation exit surface and protect the treatment surface from radiation, and that allows the treatment surface to be protected from radiation for a predetermined or adjustable or controllable time, eg aperture or A bacteria removal laser, characterized in that a mirror is provided. The method according to any one of claims 1 to 7,
The control device of the bacteria removal laser measures the temperature of the treated surface and increases the measured temperature (

) Is connected to a temperature sensor that switches off the bacteria removal laser, especially if it is greater than a predetermined threshold that is greater than the temperature increase in the wet treatment volume and greater than the temperature increase in the maximum dry treatment volume. . The method according to any one of claims 1 to 8,
The sensor is a bacteria removal laser characterized in that it detects reflected, transmitted or emitted radiation from the treated surface at the pulse stop. The method according to any one of claims 1 to 9,
The radiation exit surface and / or the treatment surface comprises a diameter of 3 to 5 mm and / or the bacteria removal laser comprises a light source with visible light, the light source emits in addition to the laser radiation source, and is visible A bacteria removal laser characterized by directing light through a radiation exit surface and projecting it onto the treatment surface, to illuminate it. The method according to any one of claims 1 to 10,
The laser is assigned a sterilizing water source, and after the switching off of the laser by the sterilizing water source-not during the switching-on state of the laser-the treatment surface is bacterial removal laser characterized in that it can be moistened with sterile water . Use of the bacterial removal laser according to any of claims 1 to 11 for removing caries bacteria, in particular for worsening its metabolism, its genetic makeup and / or for fatal damage. A system comprising a bacteria removal laser and a treated surface,
The laser emits radiation in the wavelength range of 1500 to 4500 nm, in particular more than 2200 nm, and delivers it to a treatment surface that forms the surface of hard tissue, especially dental enamel and / or dentin,
The radiation is absorbed at less than half per mm pass depth during the start of radiation delivery, especially 20 to 35%, thus damaging the bacteria and the radiation is an average energy over time of 0.01 mJ / mm ² to 10 mJ / mm ² A system characterized by reaching the treated surface at a density. The method of claim 13,
The laser emits the radiation for 1 to 30 minutes, and if necessary, by changing the power of the laser or by changing the pulse / stop ratio and / or through an increase in temperature and / or through drying of the hard tissue, at least 0.3 mm. A system characterized in that the depth of passage of radiation into the hard tissue leading to increases over this time. The method according to claim 13 or 14,
The wavelength emitted is in the microwave range, in particular about 2.4 GHz, and the laser is a system characterized in that in this regard it is designed as a major (Maser).

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